BACKGROUND OF THE INVENTION

Pneumatic wheels with inner air-tubes have been widely used in bicycles, cars, trucks, airplanes, etc. For these applications, long-term reliability of the driving behavior and sufficient comfort are important criteria. Pneumatic wheels are sensitive to cracks, puncture, and/or other damages which can lead to a leak in the inner air-tube. Sudden leaks are also a safety problem. To overcome such problems, so-called run-flat tires have been developed which comprise pneumatic tires with extended mobility in order to be able to further use the tire in case of a leackage for a certain distance (e.g. to reach the next workshop).

Such run-flat systems are described for example in US 2021/252918 A1 , US 2016/167454 A1 , US 2017/057286 A1 , DE 20 2020 102648 U1 , US 2007/199636, JP H11 59144 A or in CN 1899860 A.

Another approach to overcome the risk of a sudden tire leak is the development of non-pneu- matic wheels, which do not suffer from such leaks. A variety of non-pneumatic tires have been developed.

CN 107253340 A relates to a solid inflation-free all-plastic wheel manufacturing method and a product thereof. The disclosed product particularly comprises a carbon fiber wheel skeleton, an expanded thermoplastic polyurethane (E-TPU) tire core connected to the carbon fiber wheel skeleton in a sleeved mode and cast-polyurethane elastomer (CPU) tire tread arranged on the E-TPU tire core in a bonded mode.

WO2019/134925 A1 discloses a polyurethane composite layer which comprises a polyurethane matrix material and a thermoplastic expandable polymer material dispersed in the polyurethane matrix material. The non-pneumatic tire in WO2019/134925 A1 shows high resistance, reduced weight, and hydrolysis resistance. Still non-pneumatic tires made of a polymeric foam material are more susceptible to warpage and other deformations than pneumatic tires.

WO 2019/185687 A1 discloses a non-pneumatic tire comprising a polyurethane matrix and expanded thermoplastic elastomer particles, wherein said non-pneumatic tire comprises 60 to 90 wt% of a polyurethane matrix and 10 to 40 wt% of expanded thermoplastic elastomer particles. However, the tires often show insufficient comfort in comparison to pneumatic tires, have a higher rolling resistance and a lower long-term stability in comparison to pneumatic tires. WO2017/039451 A1 and WO2018/004344 A1 disclose non-pneumatic tires and vehicle wheel assemblies, which comprise a wheel rim having two opposed circular rim flanges; an outer tire having two tire beads secured at the circular rim flanges; an inlay; a non-pneumatic inner tire comprising expanded thermoplastic polyurethane (E-TPLI), which inner tire is enclosed by the outer tire, the inlay, and the wheel rim. The tires disclosed in WO2017/039451 A1 and

WO2018/004344 A1 show sufficient comfort in comparison to pneumatic tires but have a higher tendency to develop imbalances in comparison to pneumatic tires.

For non-pneumatic wheels it is desirable to use wheel-inlays with a high dimensional stability which may be achieved by harder foam-material or even non-foamed material. However, harder foam-material or non-foamed material as inlay leads to lower comfort and reduced rebound. It was therefore an object of the present invention to provide a molded article as inlay for non- pneumatic wheels to overcome the disadvantages of non-pneumatic wheels resulting in longterm dimensional stability, stable concentricity without the development of imbalances while retaining driving comfort and rebound properties. In addition, it would be desirable to have a wheel assembly which is at least partially recyclable.

SUMMARY OF THE INVENTION

The problem is solved by the features of the independent claims. Preferred embodiments of the present invention are provided by the dependent claims.

The invention therefore relates to a wheel assembly for non-pneumatic tires comprising an annular and radially symmetric molded article as inlay with a component A, which is partially surrounded by a component B, wherein component A is a non-foamed polymeric material, component B is a polymeric foam, component A and B are in a form-fitting connection and, wherein the molded article is placed between the outer tire (6) and the wheel rim (1) and, wherein the majority by weight of component A is made of a thermoplastic elastomer and, wherein the majority by weight of component B is made from the same thermoplastic elastomer.

In a preferred embodiment component A of the molded article comprises thermoplastic polyurethane.

In a preferred embodiment of the wheel assembly component B is selected from the group of foams consisting of thermoplastic elastomer, thermoplastic polymer, polyurethane, polyamide, polyolefin, polyethylene, polypropylene, polystyrene, and mixtures thereof. In a preferred embodiment the wheel assembly comprises a wheel rim with a rim base (1) and two rim flanges (2), an inlay, an outer tire (6) with two beads (4), which are interlocked with the rim flanges (2), wherein the inlay is in a form fitting connection with the wheel rim and the outer tire (6) and, wherein component A of the inlay forms an annular stabilization core (3) which is placed on the rim base.

In a preferred embodiment of the wheel assembly the cross-section perpendicular to the rotational plane of the annular stabilization core (3) of the inlay is a compression spring which is in a snap-connection with the wheel rim.

In a preferred embodiment of the wheel assembly component A and B of the inlay are fused, glued, or plugged together.

A further aspect of the invention relates to a process for the manufacturing of a molded article as inlay for non-pneumatic wheels comprising the steps of

(i) placing component A in a mold of a molding machine,

(ii) provide expanded particle foam beads for component B,

(iii) filling the beads into the mold in a way that the beads at least partially surround component A

(iv) fusing the particle foam beads into component B,

(v) optionally fusing component A and B.

In a preferred embodiment the methods in step (iv) and step (v) are selected from the group consisting of steam chest molding, radio frequency (RF) molding, thermal molding, molding with pressure and combinations thereof.

A further aspect of the invention relates to a wheel assembly, comprising a wheel rim with a rim base and two opposed circular rim flanges, an outer tire with two beads, which are interlocked with the circular rim flanges and which comprises the molded article according to the present invention.

A further aspect of the invention relates to the use of the wheel assembly as inlay for non-pneu- matic wheels for industrial applications, sport applications, transportation applications, leisure activities, cars, bikes, motorcycles, hand trucks, e-scooter, toys, sport equipment, golf caddy, stroller, or wheelchairs. DETAILED DESCRIPTION OF THE INVENTION

With regards to the invention, the following can be stated specifically:

According to the present invention, the object is solved by a wheel assembly for non-pneumatic tires comprising an annular and radially symmetric molded article as inlay with a component A, which is partially surrounded by a component B; wherein component A is a non-foamed polymeric material, component B is a polymeric foam, component A and B are in a form-fitting connection and, wherein the molded article is placed between the outer tire (6) and the wheel rim (1) and, wherein the majority by weight of component A is made of a thermoplastic elastomer and, wherein the majority by weight of component B is made from the same thermoplastic elastomer.

Surprisingly, it was found that in contrast to pneumatic wheels with inner air-tubes, the wheel assembly for non-pneumatic wheels according to the present invention is less sensitive for plastic deformations caused by affecting forces and temperature variations. The annular and radially symmetric molded article used as inlay for the inventive non-pneumatic wheels does adapt to the cavity geometry of outer tire and wheel rim and, therefore, the present assembly of non- pneumatic tires enables that even after long periods without use of the vehicles or intense use of the wheels do not result in imbalances at the wheels and do not impair the concentricity of the wheels. Due to avoiding such imbalances, rolling resistance, energy input and wear of the wheels are constant. Furthermore, high dimensional stability is observed.

The use of the same thermoplastic elastomer for both components of the inlay of the inventive non-pneumatic wheels allows for recycling both components together for example by means of shredding followed by re-extrusion and re-granulation or by means of agglomeration.

Component A

In a preferred embodiment component A is non-foamed polymeric material selected from the group consisting of thermoplastic elastomers, duroplastic materials, polypropylene, polyethylene terephthalate, polyamides, polyethylene, polyoxymethylene, semi-aromatic polyesters, polycarbonate, thermoplastic polyurethane, polyurethanes and mixtures thereof.

Most preferable thermoplastic elastomers, thermoplastic polyurethanes, polyamide, or polyurethane are used as material for component A. According to a further embodiment, component A and component B comprise the same polymeric material, wherein same polymeric material means that the major polymer on which component A is based and the major polymer on which component B is based have the same repeating units in their polymer chains or their glass transition temperatures do not differ more than 10 K or they belong to the same class of shore-hardness. Major polymer means the polymer with the highest share in the composition. In a preferred embodiment both, component A and component B comprise a thermoplastic polyurethane.

It is preferred that the use for non-pneumatic tires requires a sufficient bending and tensile strength, toughness, and sufficient fatigue strength. Preferably material compositions for component A with a bending strength measured according to ISO178 of at least 50 MPa, a tensile modulus measured according to ISO527 of at least 1200 MPa and a notched impact strength (Charpy notched impact strength at 23°C according to ISO179) of at least 5 kJ/m ² are used. Preferably the bending fatigue strength of the material composition of component A is at least 15 MPa (measured according to ASTM D671 , 107 cycles).

The mechanical properties of component A can be adjusted by suitable fillers and reinforcement materials. According to a further embodiment of the present invention, the composition of component A comprises a filler and/or a reinforcement material in an amount in the range from 0.1 to 20 wt.-% based on weight of the composition. Reinforcement materials comprises short and long fibers and textiles, wherein textiles can be wovens and non-wovens.

The filler and I or reinforcement material may for example be selected from the group consisting of organic fillers such as polystyrene, polyethylene, polypropylene, polyethylene terephthalate, polycarbonates, polyamides, polybutylene terephthalate, polyethylene terephthalate, polylactid acids, aramid fibers and mixtures thereof.

Inorganic fillers and reinforcement materials such as talcum, chalk, carbon black, carbon fibers or steel fibers can also be used in the context of the present invention. Suitable fillers and reinforcement materials are in principle known to the person skilled in the art.

Component A can be prefabricated as semifinished product. In principle, all suitable methods for the prefabrication of component A can be used according to the present invention, for example injection molding, injection compression molding, centrifugal casting, or 3D printing. In one embodiment component A comprises polyurethane and is prefabricated by a reaction injection molding process wherein the components are mixed and afterwards are injected into a mold to undergo a chemical reaction and form the final polyurethane part. According to a further embodiment a fiber- re info reed polyurethane based component A is produced by resin transfer molding (RTM) which is characterized by overmoulding textile or fibrous inserts with the polyurethane premixture in a heated mold and, due to the heat, induce the reaction into the polyurethane composite part.

Another aspect in the context of present invention is the design of the molded part for the targeted applications in the field of non-pneumatic tires. Component A forms an annular stabilization core which is designed rotationally symmetric and, therefore, supports the concentricity of the wheel assembly. The cross-section perpendicular to the rotational plane of the annular stabilization core can be of any shape which supports the dynamic target properties of the tire such as stable driving performance even when turning corners. Preferably the cross-section perpendicular to the rotational plane of the annular stabilization core is V-shaped, hook-shaped, circular or comprises multiple bridges. In one embodiment according to the present invention the cross-section perpendicular to the rotational plane of the annular stabilization core formed by component A is a compression spring which snaps in the surrounded inner tire formed by component B and I or the wheel rim.

Component B

Component B according to the present invention comprises a polymeric foam material. The foam is for example a particle foam or a non-particular foam. Foams, especially particle foams, have long been known and have been widely described in the literature, e.g., in Ullmann’s “Encyclopedia of Technical Chemistry”, 4th edition, volume 20, p. 416 ff.

The polymeric foam used for component B is based on a polymer selected from the group consisting of thermoplastic elastomer (TPE), thermoplastic polymer, polyurethane (Pll), polyamide (PA), polyolefin (PO), polyethylene (PE), polypropylene (PP), polystyrene (PS), and mixtures thereof. Preferably polypropylene (PP), polyamide (PA), polyether block amide (PEBA), styrene polymers, polyethylene-vinyl-acetate (EVA) or thermoplastic elastomer (TPE), such as thermoplastic polyurethane (TPU), styrenic block copolymers (TPS), thermoplastic polyolefinelastomer (TPO), thermoplastic vulcanisate (TPV), thermoplastic copolyester (TPC), thermoplastic polyamides and mixtures of the above-mentioned polymers are used as polymeric foam. In a preferred embodiment of the present invention component B comprises a particle foam of the above-mentioned materials. Most preferably thermoplastic polyurethanes are used as particle foams.

Particle foams, which are also referred to as foamed pellets (or bead foams, particle foam, expanded thermoplastic elastomer particles), and molded articles made therefrom, based on thermoplastic polyurethanes or other thermoplastic elastomers, are known (for example WO 94/20568A1 , WO 2007/082838 A1 , WO2017/030835 A1 , WO 2013/153190 A1 , WO 2010/010010 A1) and can be used in many ways.

A foamed pellet or also a particle foam or bead foam in the sense of the present invention refers to a foam in the form of a particle, the average length of the particles preferably being in the range of 1 to 10 mm. In the case of non-spherical, e.g., oval particles average length means the longest dimension by length, (determined by 3D evaluation of the granules, for example by means of dynamic image analysis with an optical measuring device named “PartAn 3D”, Microtrac).

The single foam granules according to the present invention have an average mass in the range of 0,1 to 50 mg, preferable in the range between 0,5 and 40 mg and most preferably in the range between 1 and 7 mg. The average mass means in this context the arithmetic mean based on a sample size of 10 different particles wherein each particle is weighted three times.

Suitable thermoplastic elastomers for producing the foams, moldings, or molded articles according to the invention are known to the person skilled in the art. Suitable thermoplastic elastomers are described, for example, in “Handbook of Thermoplastic Elastomers”, 2nd edition June 2014.

Suitable production processes for producing foamed pellets from thermoplastic elastomers are known to the person skilled in the art. There are two methods to obtain expanded thermoplastic particle foams, namely the extrusion method, described e.g., in W02007/082838 or W02013/153190, and the suspension method as explained for example in W02007/082838. If, according to the invention, foamed pellets made from thermoplastic elastomers are used, the bulk density of the foamed pellets is, for example, in the range of 20 g/l to 300 g/l.

The foamed pellets according to the invention usually have a bulk density of 50 g/l to 250 g/l, preferably 60 g/l to 200 g/l, more preferably 100 g/l to 180 g/l. The bulk density is measured analogously to DIN ISO 697, wherein the determination of the above values in contrast to the standard, a vessel with 10 I volume is used instead of a vessel with 0,5 I volume, since especially for the foam particles with low density and large mass a measurement with only 0,5 I volume is too inaccurate.

The particle foam according to the present invention can optionally be optimized by additives such as for example dyes, process aids or stabilizers. The additives may be added during the generation of the precursor of the particle foam or during the foaming step.

A further object of the present invention is a two-component molded article comprising component A and component B, wherein component B forms the foamed inner tire and is prepared from the foamed granules.

In one embodiment of the present invention component B is obtained by fusing the expanded foam beads into the molded part.

According to the invention, two or more types of particle foam can be used to obtain component B, wherein the used types of particle foam may differ in their polymer basis, particle shape and size or their density.

The preparation of the corresponding foam moldings can be carried out according to the skilled person known methods.

A preferred method for the preparation of a foam molding part includes the following steps

(A) Inserting the foamed granules according to the invention in a corresponding mold,

(B) Fusing the foamed granules according to the invention from step (A).

The fusion in step (B) preferably takes place in a closed mold, wherein the fusion can be carried out by steam, hot air or energetic radiation (microwaves, radio waves or infrared waves).

The temperature at the fusion of the foamed granules is preferably below or close to the melting temperature of the polymer from which the particle foam was produced. For the common polymers, therefore, the temperature for fusion of the foamed granules is between 80 °C and 180°C, preferably between 120°C and 150°C.

Temperature profiles I residence times can be determined specifically for the used materials, e.g., in analogy to the methods described in LIS20150337102 or EP2872309. Fusing by steam is carried out on commercial steam chest molding machines which can be modified in their design. Typical steam pressures to be applied for particle foam beads out of thermoplastic elastomers, such as thermoplastic polyurethanes, are between 0,8 bar and 5 bar, more preferably between 0,8 bar and 2,5 bar. By means of the steam pressure the temperature for bonding the particle foam beads within the mold is adjusted.

The foamed granules can be conveyed into the shaping tool manually or automated by using pressurized air. The shaping tool also referred to as mold or molding tool comprises two primary components, the injection mold-plate with the filling nozzles, and a counterpart-plate. To generate the molding part, both mold-plates are pressed together so that a cavity in the shape of the molding part is formed. The filling of the mold-cavity can be conducted either by crack filling method or by the pressure filling method. The crack-filling method comprises the following steps:

(A) injecting the expanded foam-particles into the mold-cavity without a backpressure of the counterpart-plate,

(B) fusing the particles by the application of steam while closing the plates of the mold mechanically,

(C) cool down the molding part and

(D) demold the produced part, wherein in step (A) due to the lack of backpressure a gap between the injection mold-plate and the counterpart-plate arises. The mold-cavity is filled completely with the expanded beads in step (A). In step (B) the volume of the mold-cavity is reduced compared to step (A), because the two parts of the molding tool are closed tightly and the intermediate gap is, thus, disappeared. This leads to a pressure increase within the mold-cavity. The expanded beads are thus pressed against one another and can therefore become fused to give the molding. In particular, the fusion is achieved via passage of steam through the system.

The pressure filling method comprises the following steps:

(A) injecting the expanded foam-particles into the mold-cavity by pneumatic pressure while compressing both plates of the mold tightly together,

(B) fusing the particles by the application of steam,

(C) cool down the molding part,

(D) demold the produced part.

Since the exerted injection pressure in step (A) is ceased in step (B) the inserted foam beads may further expand and as a result be pressed against one and another and, therefore, become fused and give the molding. Three different steaming-methods can be used in the molding machine to fuse the foamed particles: crack steaming (only when applying the crack-filling method), cross-steaming and autoclave steaming. Cross steaming strongly supports the bonding between the particles inside the molding part. The steam flows through the filled mold cavity from one side of the mold to the other side first and then the flow is changed into the opposite direction. In contrast, in case of autoclave steaming the steam comes from both sides of the molding tool at the same time.

Fusing by energetic radiation is generally carried out in the microwave-frequency range of 300 MHz - 300 GHz or in the radio-frequency range of 30 kHz - 300 MHz Microwaves are preferably applied in the frequency range between 0,5 and 100 GHz, especially preferably in the range between 0,8 and 10 GHz and irradiation times between 0,1 and 15 min are used. Radio waves are preferably applied in the frequency range between 500 kHz and 100 MHz, especially preferably in the range between 1 MHz and 80 MHz and irradiation times between 0,1 and 30 min are used. The energy may be supplied by electromagnetic induction. For this purpose, a dielectric molding-tool is placed in between two capacitor plates which generate a dielectric field. The expanded foam beads are loaded into the cavity of the molding tool and are heated by applying the dielectric field. As a result, the surface of the foam beads is partially molten and, therefore the beads become fused and form the molded part. To preserve the foam morphology and melt the bead surface only, the process is adapted in accordance with the used materials and the design of the molded article. In general, the energy input is controlled and adjusted by the applied voltage, the irradiation time, and the amount of material. Before the molded part can be removed from the molding tool, it must be stabilized and cooled down. The stabilization can be achieved by stopping the active heating or by means of an active cooling-procedure, such as for example described in EP3405322.

In one embodiment of the present invention, the particle foams comprise polar additives which increase the dielectric heating effect by absorbing the electromagnetic radiation. Polar additives are preferably selected from the group consisting of inorganic salts, esters of carboxylic acids and diols or triols or glycols, carbamide compounds, polyol, and glycerol. Preferably polymeric foam beads are coated with water or other polar liquids or additives comprising functional groups with hydrocarbons (such as carbamide or esters of carboxylic acids and diols or triols or glycols and liquid polyethylene glycols). Preferably the coating is applied in proportions of 0,1 to 10 wt.-%, more preferably in proportions of 1 to 6 wt.-%, based on the used particle foam.

In another embodiment of the present invention, the polymeric foam beads are coated with inorganic saline solutions such as for example sodium chloride solution prior to the fusion by means of electromagnetic radiation. Preferably the concentration of the applied saline solutions is in the range between 0,1 to 5 wt.-%, more preferably between 0,1 to 0,8 wt.-%. The above-described functionalization to increase the dielectric heating intensity of non-polar polymeric foam beads can be carried out in analogy to the methods described in EP3053732 or WO16146537. In general, polar additives are applied for polymeric foam beads which cannot be or not sufficiently be stimulated by electromagnetic radiation and, therefore, cannot be heated up without suitable additives. For this purpose, the frequency range of the applied electromagnetic radiation is adjusted to the absorption behavior of the polar coating or additive or vice versa the polar liquid or additive is selected based on the absorption behavior according to the available frequency range of the used device. Fusing polymeric foam beads based on thermoplastic polyurethane (TPU) or thermoplastic polyamides (TPA) with electromagnetic radiation can be achieved in the context of the present invention without the use of polar additives.

Basically, all suitable methods for fusing foamed beads to obtain component B can be used according to the present invention. Besides using the before described steam-chest molding or radio-frequency molding, molded parts can be obtained by means of compression molding with either directly or indirectly heated molds.

In a further embodiment according to the present invention the surface of the foam beads is wetted or sprinkled with activating additives, binders or emulsions of the additives or binders which support the fusion process within the mold by functionalization of the bead surface. Suitable methods are, for example, the ATECARMA process described in W02021/009720.

According to an embodiment, the present invention also relates to the application of adhesives for bonding the foamed particles together and by this create the molded article. Preferably, reactive adhesives that after solidifying cannot be remelt, such as for example, polyurethanes (PUR), epoxy resins or silicones are used. The reaction of the adhesives can be induced for example by heat and moisture or ultraviolet radiation. In further embodiments hot-melt adhesives or solvent based adhesives serve for bonding of the foamed particles. Usually, the gluing process takes place in a molding tool which is preferably temperature controlled.

In one embodiment of the invention component B is made of integral foams, in particular integral foams based on polyurethane. Suitable methods for production of integral foams are known to the skilled person per se. The integral foams are preferably manufactured by the one-shot process with the help of low pressure or high-pressure technology in closed, purpose-controlled molding tools. These methods are described, for example, by Piechota and Rohr in “Integral Schaumstoff’, Carl-Hanser-Verlag, Munich, Vienna, 1975, or in the Plastic Manual, Volume 7, Polyurethanes, 3rd edition, 1993, chapter 7. The reaction mixture for the generation of the integral foams according to the invention can optionally be optimized by process aids and I or additives. For example, surface-active substances, foam stabilizers, cell regulators, release agents, fillers, dyes, pigments, and hydrolysis protection agents are mentioned.

In the context of the invention polyurethane foams are understood to be foams in accordance with DIN 7726.

According to a further aspect of the present invention, the foamed inner tire formed by component B comprises a hybrid material of foamed beads which are embedded in a matrix of a polymer such as, for example, described in PCT/EP2022/051690. The matrix material can be made of a compact material or also of a polymeric foam.

Polymers suitable as matrix material are known to the skilled person themselves. Suitable in the context of the present invention are, for example, ethylene-vinyl acetate copolymers, binders based on epoxy or also polyurethanes. Preferably the foam matrix is a polyurethane foam.

According to the invention the hybrid material may contain further components, for example reinforcement fibers, fabrics, or fillers.

Connection between component A and component B

Another aspect of the present invention relates to the technique for joining component A and B of the inlay. In one embodiment of the present invention component A and component B are premanufactured separately and joined afterwards. Component A and component B can be connected detachably or non-detachably.

Suitable joining methods for polymeric parts are known to the skilled person themselves and described, for example, in “Handbuch Kunststoff-Verbindungstechnik”, Carl Hanser Verlag, 1st edition 2004.

In one embodiment of the present invention component A and component B form a non-detach- able substance-to-substance bond by fusing or gluing them together. The fusing of component A and component B - also referred to as welding - comprises the heating of the interfaces of both components close to the melting temperature of the polymer, pressing the heated interfaces together and, then allowing the weld to solidify. In principle, all kind of suitable heating methods can be applied to heat the interfaces. Preferably the heating method for the interfaces to be welded are selected from the group consisting of heating through hot steam, hot air or energetic radiation (microwaves, radio waves or infrared waves), ultrasonic heating, laser heating or friction heating. In another embodiment component A and component B are welded by using chemical solvents at the interfaces.

Gluing component A and component B together comprises the application of adhesives at the interfaces, followed by pressing the interfaces together and by this create the molded article. Preferably, reactive adhesives that after solidifying cannot be remelt, such as for example, polyurethanes (PUR), epoxy resins or silicones are used. The reaction of the adhesives can be induced for example by heat and moisture or ultraviolet radiation. In further embodiments hot-melt adhesives or solvent based adhesives serve for bonding of the interfaces.

In another embodiment of the present invention component A and component B are joined detachably by for example plugging or pushing parts of component A into one or more recesses of component B as described on the following pages. Preferable embodiments in this context are illustrated on the attached figures. The connection between component A and component B can be realized in a form-locking and I or force-locking manner.

According to another embodiment of the present invention component A is partly overmolded with component B, for example, by fusing the particle foam beads into component B with component A as insert with a suitable two-component molding machine.

In a preferred embodiment the process for the manufacturing of a molded article as inlay for non-pneumatic wheels comprises the steps of

(i) placing component (A) in a mold of a molding machine,

(ii) provide expanded particle foam beads for component (B),

(iii) filling the beads into the mold in a way that the beads at least partially surround component (A),

(iv) fusing the particle foam beads into component (B),

(v) optionally fusing component (A) and (B), wherein the steps (iv) and (v) can be conducted either sequentially or in parallel.

In another embodiment the process for the manufacturing of a molded article as inlay for nonpneumatic wheels comprises the steps of

(i) placing component (A) in a mold of a molding machine,

(ii) provide a reactive polyurethane foam system for component (B),

(iii) mixing the components of the polyurethane foam system, (iv) injecting the polyurethane foam system into the mold in a way that component A is at least partially surrounded by component (B). after the polyurethane foam is stabilized and cured removing the final inlay.

Form-fitting connection

Component A and component B are in a form-fitting connection. Component A forms the annular stabilization core which is placed on the wheel rim base and component B forms the foamed inner tire which is surrounded by the outer tire. The form-fitting connection is caused by interlocking of component A and component B in such a way that a separation between component A and component B doesn’t occur even without or interrupted load. The joint components block each other at least at one joint interface and, therefore, avoid shifting between component A and B.

In a preferred embodiment the form fit is realized through recess within the foamed inner tire formed by component B as negative part in which the annular stabilization core formed by component A fits in as positive part (see Fig. 1 , 2 and 5).

According to a further embodiment the recess of foamed inner tire formed by component B is shaped as undercut (see Fig. 5).

According to a further embodiment the annular stabilization core formed by component A and the foamed inner tire formed by component B are in a tongue-and-groove joint.

According to a further embodiment the cross-section of the annular stabilization core formed by component A is V-shaped with the long side positioned at the wheel rim base (see Fig. 1 and Fig. 2) and an appropriate formed slit in the foamed inner tire formed by component B.

According to a further embodiment the rotational plane of the annular stabilization core formed by component A is a compression spring (see Fig. 4) which is in a snap-connection with the foamed inner tire formed by component B (see Fig. 3).

In a further embodiment, the foamed inner tire formed by component B exhibits more than one grooves, and the annular stabilization core formed by component A comprises the same number of bridges (9), wherein the bridges form-fit in the grooves. According to a further aspect, the present invention is directed to a use as inlay for non-pneu- matic wheel assemblies, wherein the inlay is in a form-fitting connection with a wheel assembly comprising a wheel rim with a rim base and two rim flanges, an outer tire with two beads, which are interlocked with the rim flanges.

In a preferred embodiment, the annular stabilization core formed by component A of the inlay is placed on the rim base and is laterally interlocked by the rim flanges (see Fig. 1, 2, 3, 5 and 6). In a more preferred embodiment, a part of the annular stabilization core formed by component A completely fills the space between rim base and rim flanges and, thus, cannot slip laterally.

According to a further embodiment the rotational plane of the annular stabilization core formed by component A is a compression spring which is in a snap-connection with the wheel rim (see Fig. 5).

The outer tire is tightly mounted on the inner rim flanges and the inlay. For this purpose, the two beads of the outer tire are fixed between the inner rim flanges and component A of the inlay (see Fig. 1 , 2, 3, 5, 6).

Use of the molded article

The molded article according to the present invention is directed to a use as inlay for non-pneu- matic wheels for industrial applications, sport applications, transportation applications, leisure activities, cars, bikes, motorcycles, hand trucks, e-scooter, toys, sport equipment, golf caddy, stroller, or wheelchairs.

The invention relates to a molded article as inlay for non-pneumatic wheel assemblies comprising a component A, which is partially surrounded by a component B, wherein A is a non-foamed polymeric material, component B is a polymeric foam, component A and B are in a form-fitting connection.

In a preferred embodiment component A of the molded article is selected from the group consisting of thermoplastic elastomers, duopolistic materials, polypropylene, polyethylene terephthalate, polyamides, polyethylene, polyoxymethylene, semi-aromatic polyesters, polycarbonate, thermoplastic polyurethane, and mixtures thereof. In a preferred embodiment component B of the molded article selected from the group of foams consisting of thermoplastic elastomer, thermoplastic polymer, polyurethane, polyamide, polyolefin, polyethylene, polypropylene, polystyrene, and mixtures thereof.

In a preferred embodiment the molded article also referred to as inlay is in a form-fitting connection with a wheel assembly comprising a wheel rim with a rim base and two rim flanges, an outer tire with two beads, which are interlocked with the rim flanges, wherein component A of the inlay is placed on the rim base.

In a preferred embodiment the cross-section perpendicular to the rotational plane of component A is a compression spring which is in a snap-connection with the wheel rim.

In a preferred embodiment component A and B of the inlay are fused, glued, or plugged together.

In a preferred embodiment the majority by weight of component A is made of a thermoplastic elastomer and, wherein the majority by weight of component B is made from the same thermoplastic elastomer.

A further aspect of the invention relates to a process for the manufacturing of a molded article as inlay for non-pneumatic wheels comprising the steps of

(i) placing component A in a mold of a molding machine,

(ii) provide expanded particle foam beads for component B,

(iii) filling the beads into the mold in a way that the beads at least partially surround component A

(iv) fusing the particle foam beads into component B,

(v) optionally fusing component A and B.

In a preferred embodiment the methods in step (iv) and step (v) are selected from the group consisting of steam chest molding, radio frequency (RF) molding, thermal molding, molding with pressure and combinations thereof.

A further aspect of the invention relates to a process for the manufacturing of a molded article as inlay for non-pneumatic wheels comprising the steps of i. placing component A in a mold of a molding machine, ii. provide a reactive polyurethane foam system for component B, iii. mixing the components of the polyurethane foam system, iv. injecting the polyurethane foam system into the mold in a way that component A is at least partially surrounded by component B. v. after the polyurethane foam is stabilized and cured removing the final inlay. A further aspect of the invention relates to a wheel assembly, comprising a wheel rim with a rim base and two opposed circular rim flanges, an outer tire with two beads, which are interlocked with the circular rim flanges and which comprises the molded article according to the present invention. A further aspect of the invention relates to the use of the molded article according to the invention as inlay for non-pneumatic wheels for industrial applications, sport applications, transportation applications, leisure activities, cars, bikes, motorcycles, hand trucks, e-scooter, toys, sport equipment, golf caddy, stroller, or wheelchairs.

Illustrative embodiments of the invention are shown in the figures and explained in more detail in the following description.

FIGURES

Brief description of the figures

Fig. 1 Cross-sectionial view of a wheel with a two-component molded article as inlay, wherein component A forms a V-shaped stabilization core.

Fig. 2 Cross-sectional view of a deformation of a wheel with the two-component molded article as inlay under load.

Fig. 3 Cross-sectional view of a wheel with a two-component molded article as inlay, wherein component A forms an annular stabilization core which is in a snap-connection with component B.

Fig. 4 Cross-sectional view of the annular stabilization core designed as compression spring for snap-connections in a released state.

Fig. 5 Cross-sectional view of the annular stabilization core designed as a compression spring for snap-connection in a compressed state.

Fig. 6 Cross-sectional view of a wheel with a two-component molded article as inlay, wherein component A forms an annular stabilization core which is in a snap-connection with the wheel rim and the recess of the foamed inner tire is shaped as undercut.

Fig. 7 Cross-sectional view of a wheel with a two-component molded article as inlay, wherein the annular stabilization core and the foamed inner tire form a tongue-and-groove joint.

Fig. 8 Three-dimensional display of a wheel section with a two-component molded article as inlay, wherein component A forms an annular stabilization core which is V-shaped.

Detailed description of the figures

In Fig. 1 shows a cross-sectional view of a wheel with the molded article as inlay. The wheel comprises a wheel rim with a rim base (1) and two rim flanges (2) and an outer tire (6). The outer tire comprises two beads (4), which can interlock with the wheel rim flanges (2). The inlay of the wheel comprises an annular stabilization core (3) which is partially embedded in a foamed inner tire (5). The annular stabilization core is placed on the wheel rim base (1) and is formed from component A. The design of the stabilization core (3) adapts the geometry of the rim base (1) and, therefore, avoids hollow cavities between rim base (1) and stabilization core (3). The foamed inner tire (5) is surrounded by the outer tire (6) and formed from component B. The stabilization core (3) and the foamed inner tire (5) are in a form-fitting connection. Optionally the stabilization core (3) and the foamed inner tire (5) are fused or glued together. Furthermore, the stabilization core (3) and the foamed inner tire (5) are radially symmetric and are positioned centrally related to the wheel rim base (1). The illustrated embodiment of the molded article in Fig. 1 shows a V-shaped cross section of the stabilization core (3) with the long side positioned at the wheel rim base (1).

Fig. 2 shows a cross-sectional view of the same wheel under load, which for example arises from cornering at the wheel. The radially symmetric position of the annular stabilization core (3) is laterally fixed by the rim flanges (2) and is kept even under load. Due to the high bending strength of the used non-foamed material the shape of the annular stabilization core (3) remains unchanged under load. The foamed inner tire (5), which is surrounded by the outer tire (6), is slightly asymmetrically deformed. However, the radially symmetric fixing by the bending resistant annular stabilization core (3) prevents a strong deformation of the outer tire (6) with the encased foamed inner tire (5), ensures reversibility of the deformation and, therefore, maintains the concentricity of the wheel.

Fig. 3 shows a cross-sectional view of a wheel with a two-component molded article as inlay. The illustrated wheel assembly is the same as described for Fig. 1 with a wheel rim base (1), two rim flanges (2), a non-foamed component of the inlay as annular stabilization core (3), a foamed inner tire (5) and an outer tire (6). But, in contrast to the illustrated embodiment in Fig. 1 and Fig. 2, the annular stabilization core (3) is designed as compression spring. The elasticity of the foamed inner tire (5) is used to push the annular stabilization core (3) into the recess of the foamed inner tire (5) so that they form an interlocking connection. Protruding edges (7) of the annular stabilization core (3) and a compatible snap-in area in the foamed inner tire (5) ensures that the foamed inner tire (5) is hold in a fixed position.

In Fig. 4 and Fig. 5 the annular stabilization core (3) designed as compression spring for snapconnections is shown separately. In a released state as shown in Figure 4 maximum width of the stabilization core (3) is given by the distance d1 between the two protruding edges (7). To insert the annular stabilization core (3) into the foamed inner tire (5) the lower part of the annular stabilization core (3) has to be compressed as illustrated in Figure 5. In the compressed state as shown in Figure 5 maximum width of the annular stabilization core (3) is given by the distance d2 between the protruding edges (7), wherein d2 is smaller than d1. Thus, the compression narrows the width of the annular stabilization core (3) and, therefore, it can easily slide in the snap-in area of the foamed inner tire (5) without being hindered by the protruding edges (7) of the annular stabilization core (3).

Fig. 6 shows a cross-sectional view of a wheel with a two-component molded article as inlay. The illustrated wheel assembly is the same as described for Fig. 3 with a wheel rim base (1), two rim flanges (2), an annular stabilization core (3) which is partially embedded in a foamed inner tire (5). The annular stabilization core is placed on the wheel rim base (1) and is formed from component A. The foamed inner tire (5) is surrounded by the outer tire (6) and formed from component B. The annular stabilization core (3) is designed as compression spring as well. But, in contrast to the illustrated embodiment in Fig. 3, the annular stabilization core (3) forms a snap-connection with the wheel-rim comprising the wheel-rim base (1) and the two rim flanges (2). The recess of the foamed inner tire (5) is designed as undercut (8). The elasticity of the foamed inner tire (5) is used to push the annular bulge of the stabilization core (3) into the recess of the foamed inner tire (5) so that they form an interlocking connection. The undercut (8) of the foamed inner tire (5) prevents shifting between annular stabilization core (3) and foamed inner tire (5).

Fig. 7 shows a cross-sectional view of a wheel with a two-component molded article as inlay. The illustrated wheel assembly is similar as described for Figures 1 , 3 and 6 with a wheel rim base (1), two rim flanges (2), an annular stabilization core (3) which is partially embedded in a foamed inner tire (5). The annular stabilization core is placed on the wheel rim base (1) and is formed from component A. The foamed inner tire (5) is surrounded by the outer tire (6) and formed from component B. However, Figure 7 illustrates a specific embodiment, wherein the annular stabilization core (3) and the foamed inner tire (5) form a tongue-and-groove joint. In the illustrated embodiment the foamed inner tire (5) exhibits three grooves and the annular stabilization core (3) three bridges (9) accordingly. The bridges (9) form-fit in the grooves of the foamed inner tire (5).

In Fig. 8 a three-dimensional display of a wheel section with a two-component molded article as inlay is shown. The illustrated wheel assembly is the same as described for Fig. 1 and Fig. 2 with a wheel rim base (1), two rim flanges (2), an annular stabilization core (3) which is partially embedded in a foamed inner tire (5). The annular stabilization core is placed on the wheel rim base (1) and is formed from component A. The foamed inner tire (5) is surrounded by the outer tire (6) and formed from component B. The cross-section of the annular stabilization core (3) is designed as V-shape as well.